IF tcyandy is talking about a direct-drive, ungeared engine, then there is ONLY ONE TORQUE to consider. It is the torque the engine crankshaft delivers to the prop.
You may call it prop torque, or engine torque, as you like - but they are THE SAME THING.
If there's a gearbox in the system, then there are an input torque (i.e. crankshaft) and an output torque (i.e. prop). If the gear ratio is 2:1, then rpm is halved, and torque is doubled (well, almost, minus a very small heat loss).